In web searches, a user wants the most relevant results (e.g., a list of links ranked by relevance) returned in response to a query. Traditionally, relevance has been represented by conventional models such as BM25, language modeling for information retrieval, proximity modeling, and so forth.
However, results returned in response to a web search that uses one of these conventional models are not always the most relevant. Even when the most relevant material is returned among a list of URLs, links are often not properly ranked by relevance. Any mechanism that can return more relevant results and/or ranks relevant results relative to one another according to relevance is valuable in web search technology.